There are, of course,numerous devices for conveying, particularly with displays, information to the users of broadcast receivers, particularly, home and auto radio receivers. Such displays have taken the form of 7-segment gas diodes, light emitting diodes and even liquid crystal display panels to provide the user information about the frequency of the station to which he is listening. An example of a liquid crystal display is shown in the U.S. Pat. No. to Schiebelhuth 4,040,719. Another such patent is the U.S. Pat. No. to Oshawa 4,123,714. In this patent, the liquid crystal display merely advises the user whether the broadcast is stereo or monaural. Still another patent concerned with displaying the broadcast frequency to the user is the U.S. Pat. No. to Froeliger 4,495,651.
A conventional scanning receiver is one which can be operated to scan over a portion of the broadcast frequency spectrum to stop at a received station having a sufficient signal strength and permit a user to listen to or watch that station. Such receivers, for instance, are often provided in vehicles and operated to scan either AM or FM bands to stop at the first station received for a period of time to permit the user to decide if the station received is one he wants to listen to or to let the scanning operation resume.
There are currently several systems which are used to provide automatic station-identification of broadcast stations on a broadcast receiver. Reference is made in particular to the ID LOGIC system as described in application Ser. No. 07/078,286 for DISPLAY FOR RADIO RECEIVER filed Jul. 27, 1987 and its Continuation-In-part Applications Ser. No. 212,863 for BROADCAST RECEIVER CAPABLE OF SELECTING STATIONS BASED UPON GEOGRAPHICAL LOCATION AND PROGRAM FORMAT filed on Jun. 29, 1988 U.S. Pat. No. 4,969,209, and Ser. No. 07/515,629 for BROADCAST RECEIVER CAPABLE OF AUTOMATICALLY UPDATING LOCATION AND PERFORMING SPIRAL SEARCHING filed on Apr. 27, 1990, U.S. Pat. No. 5,152,011, as well as the RADIO DATA SYSTEM (RDS) as published in the public domain in the Technical Journal Tech. 3244-E titled SPECIFICATIONS OF THE RADIO DATA SYSTEM RDS FOR VHF/FM SOUND BROADCASTING by the European Broadcasting Union.
The later publication is directed to a system in which digital coded data containing, amongst other things, the broadcasting station information is sent via an FM subcarrier along with main program contents. This subcarrier digital data is then decoded at the receiver for display on the receiver display means. The limitation of this system stems from three problems: (1) this system can only perform adequately in the FM band; (2) to be effective, every FM radio station must be equipped with a subcarrier encoding system; and (3) format-scanning is only possible after the receiver has interrogated all of the FM stations in its receiving range.
The ID LOGIC system, on the other hand, is based on a large internal preprogrammed database in a memory means such as a Read-Only Memory (ROM) which can contain station information for all stations in all bands. ID LOGIC can therefore operate in all bands without restrictions and perform format-scanning instantaneously, which is a great advantage to the user. The weakness of a system without the present invention stems from the fact that the database must be updated manually by the user--either by replacing the memory means containing the database, or by entering updated data in a memory means such as a Random Access Memory (RAM) via the front panel--the RAM data is then used by the controlling processor in place of the information in the ROM.
As broadcasters sometimes spend great sums of money to advertise format, call-letter changes and other changes pertaining to their broadcasting stations, and since receiver users will want the data stored in their receivers to reflect the latest changes in their markets, it is desirable to offer a system in which stored data can be updated as soon and as easily as practicable.
The present invention provides a means to update a receiver-integrated database containing station identification and station attribute information so that data update can be done automatically or semi-automatically through VHF/FM subcarrier data transmission as soon as a data change is known and as easily as practicable. The real benefit of the invention stems from the fact that not only the data for the station being tuned to is updated, but also the data for stations which may not have subcarrier-capable transmission capability, such as stations transmitting in a band where subcarrier data transmission is impracticable (such as in the AM band) or stations which have not made the capital expenditure necessary for the installation of such subcarrier data transmission capability.
The recent deregulation of broadcast subcarrier usage has spurred a new interest in using subcarrier for data transmission and paging services in addition to the more conventional audio services. FM and TV stations are now permitted to use up to two additional audio or data channels on the main carrier of the station. Subcarriers added to FM broadcast stations include Subsidiary Communications Authorizations (SCA) while subcarriers added to a TV station's aural carrier include a Secondary Audio Program (SAP) or a non-public channel for Professional use (PRO).